FORT WORTH, Texas — A medical examiner says a man who died in the infield during a NASCAR race at Texas Motor Speedway shot himself in the head.

The Tarrant County medical examiner’s office on Sunday said the death of 42-year-old Kirk Franklin of Saginaw was a suicide.

Fort Worth police have said a man who was camping in the infield died of a “self-inflicted injury” after getting into an argument with other campers. The incident happened late in the Sprint Cup-NRA 500 race.

Police spokeswoman Cpl. Tracey Knight has said alcohol may have been a factor. Knight said several people witnessed the incident, but nobody was in danger.

Track spokesman Mike Zizzo say the death occurred “in or around a pickup truck” in part of the infield near the middle of the backstretch.